Initial commit of library code, moved from leaftest repo

git-svn-id: https://leaflabs.googlecode.com/svn/trunk/library@69 749a229e-a60e-11de-b98f-4500b42dc123

1 files changed, 44 insertions, 0 deletions

diff --git a/src/lib/usart.c b/src/lib/usart.c
new file mode 100644
index 0000000..c1a7f43
--- /dev/null
+++ b/src/lib/usart.c
@@ -0,0 +1,44 @@
+#include "stm32f10x_rcc.h"
+#include "usart.h"
+
+static inline void usart_putc(usart_port *port, uint8_t ch) {
+    port->DR = ch;
+
+    /* Wait till TXE = 1 */
+    while ((port->SR & USART_TXE) == 0)
+        ;
+}
+
+int32_t usart_init(uint8_t usart_num) {
+    ASSERT((usart_num < NR_USARTS) && (usart_num > 0));
+    usart_port *port;
+    uint32_t clk_speed;
+
+    switch (usart_num) {
+    case 1:
+        port = USART1_BASE;
+        clk_speed = USART1_CLK;
+        break;
+    case 2:
+        port = USART2_BASE;
+        clk_speed = USART2_CLK;
+        RCC_APB1PeriphClockCmd(RCC_APB1Periph_USART2, ENABLE);
+        break;
+    case 3:
+        port = USART3_BASE;
+        break;
+    default:
+        /* should never get here  */
+        ASSERT(0);
+    }
+    uint32_t baud = 9600;
+    uint32_t usartdiv = clk_speed / baud;
+
+    /* Set baud rate  */
+    port->BRR = BIT_MASK_SHIFT(B9600_MANTISSA, 4) | B9600_FRACTION;
+
+    /* Enable the USART and set 8n1 (M bit clear) enable transmitter*/
+    port->CR1 = USART_UE | USART_TE;
+
+    return 0;
+}